While getting sweaty and sticky is one uncomfortable side effect of enjoying the summer sun, it's important to remember that the heat can do more than make you uncomfortable — it can make you sick, or worse.

Heatstroke, the most severe form of heat illness, can be fatal if left untreated. According to the CDC, extreme heat caused 7,415 heat-related deaths in the United States from 1999 to 2010.

"Elderly people and children are especially vulnerable, but anyone can succumb to heat illness," says Dr. John Shivdat, Medical Director of Emergency Medicine at Coliseum Medical Centers. "Sometimes our body's natural cooling system just can't keep up."

The good news is heat-related illnesses are preventable. To stay cool this summer and avoid heat exhaustion, heat stroke and other heat illnesses, follow these simple guidelines:

  • Never leave children, infants or pets in a parked car, even if the windows are open.
  • Wear lightly-colored, lightweight, loosely-fitting clothing to keep cool and comfortable.
  • Plan outdoor activities for the coolest times of day, such as morning or evening.
  • Stay hydrated, especially if you have to be outside for extended periods of time.

If you spot any signs of heat-related illness – such as fever, confusion or combativeness, rapid pulse, flushed skin, lack of sweating, feeling faint, staggering or coma – seek medical care immediately.

Anyone suffering from a heat-related illness should be taken to a shady or air-conditioned spot and told to lie down. Apply a cold, wet cloth to the wrists, neck, armpits and groin to help cool the blood. If the person can swallow, give them nonalcoholic fluids, like water or apple juice.